The present invention relates to iron golf clubs.
Recently, attention has been focused on iron golf clubs with heads made of titanium. Titanium has a small specific gravity and high strength. Therefore, iron golf clubs with titanium heads enable the head size to increase and hence make it possible to enlarge the sweet spot.
In the field of golf clubs with titanium heads, particularly iron clubs, there have been developed clubs in which a metal having a large specific gravity is buried in the sole to lower the center of gravity of the clubhead. However, it is technically difficult to bury a different kind of metal in the sole, and this leads to a rise in the production cost and causes the rejection rate to increase.
Conventional iron golf clubs have been designed so that the ball contacts the sweet spot on the clubface at impact. However, the research conducted by the present inventor has revealed that the farthest distance is attained when the ball contacts the sweet spot at right angles to the clubface, and that the point where the farthest distance is obtained is not the sweet spot when the clubface meets the ball at a predetermined angle of tilt as is the case with iron golf clubs.
In view of the above-described background, an object of the present invention is to provide a variety of novel clubheads and iron golf clubs with the novel heads by reexamining the conventional views that iron golf clubs with a low center of gravity have good performance, and introducing a new criterion for evaluation to obtain iron golf clubs capable of sending the ball better distance.
Another object of the present invention is to find the true point on the face of an iron golf club that sends the ball farther than any other part of the face and to provide novel clubheads having such a point and also iron golf clubs with the novel heads.
To attain the above-described objects, the present invention provides a head of an iron golf club which includes a face forming portion having a face formed on the forward surface thereof, and a sole forming portion extending rearwardly from the lower end of the face forming portion. The sole forming portion has a sole formed on the bottom thereof. The sole forming portion is provided with a hole near the face forming portion.
According to another aspect of the present invention, there is provided a head of an iron golf club which includes a face forming portion having a face formed on the forward surface thereof, and a sole forming portion extending rearwardly from the lower end of the face forming portion. The sole forming portion has a sole formed on the bottom thereof. The sole forming portion is provided with a hole closer to the face than the center of gravity of the head.
According to another aspect of the present invention, there is provided a head of an iron golf club wherein a hole is formed in a lower portion of the head near the clubface.
The hole may be elongated in the widthwise direction of the head.
The hole may extend through the sole forming portion.
According to another aspect of the present invention, there is provided a head of an iron golf club which includes a face forming portion having a face formed on the forward surface thereof, and a sole forming portion extending rearwardly from the lower end of the face forming portion. The sole forming portion has a sole formed on the bottom thereof. The sole forming portion is provided with a portion having a smaller specific gravity than that of the rest of the sole forming portion near the face forming portion.
According to another aspect of the present invention, there is provided a head of an iron golf club which includes a face forming portion having a face formed on the forward surface thereof, and a sole forming portion extending rearwardly from the lower end of the face forming portion. The sole forming portion has a sole formed on the bottom thereof. The sole forming portion is provided with a portion having a smaller specific gravity than that of the rest of the sole forming portion at a position closer to the face than the center of gravity of the head.
According to another aspect of the present invention, there is provided a head of an iron golf club wherein a lower portion of the head near the clubface is provided with a portion having a smaller specific gravity than that of the rest of the head.
The portion having a smaller specific gravity may be elongated in the widthwise direction of the head.
According to another aspect of the present invention, there is provided a head of an iron golf club which includes a face forming portion having a face formed on the forward surface thereof, and a sole forming portion extending rearwardly from the lower end of the face forming portion. The sole forming portion has a sole formed on the bottom thereof. The sole forming portion is provided with a hollow portion near the face forming portion.
According to another aspect of the present invention, there is provided a head of an iron golf club which includes a face forming portion having a face formed on the forward surface thereof, and a sole forming portion extending rearwardly from the lower end of the face forming portion. The sole forming portion has a sole formed on the bottom thereof. The sole forming portion is provided with a hollow portion at a position closer to the face than the center of gravity of the head.
According to another aspect of the present invention, there is provided a head of an iron golf club wherein a hollow portion is formed in a lower portion of the head near the clubface.
The hollow portion may be elongated in the widthwise direction of the head.
According to another aspect of the present invention, there is provided a head of a No. 2 iron golf club wherein in a state where the head has been correctly positioned with respect to a golf ball upon addressing, the angle xcex8 of intersection between a horizontal line containing a meeting point on the clubface and a line connecting the meeting point and the center of gravity of the head is in the range of from 0xc2x0 to 19.2xc2x0.
According to another aspect of the present invention, there is provided a head of a No. 3 iron golf club wherein in a state where the head has been correctly positioned with respect to a golf ball upon addressing, the angle xcex8 of intersection between a horizontal line containing a meeting point on the clubface and a line connecting the meeting point and the center of gravity of the head is in the range of from 0xc2x0 to 23.2xc2x0.
According to another aspect of the present invention, there is provided a head of a No. 4 iron golf club wherein in a state where the head has been correctly positioned with respect to a golf ball upon addressing, the angle xcex8 of intersection between a horizontal line containing a meeting point on the clubface and a line connecting the meeting point and the center of gravity of the head is in the range of from 0xc2x0 to 26.0xc2x0.
According to another aspect of the present invention, there is provided a head of a No. 5 iron golf club wherein in a state where the head has been correctly positioned with respect to a golf ball upon addressing, the angle xcex8 of intersection between a horizontal line containing a meeting point on the clubface and a line connecting the meeting point and the center of gravity of the head is in the range of from 0xc2x0 to 27.3xc2x0.
According to another aspect of the present invention, there is provided a head of a No. 6 iron golf club wherein in a state where the head has been correctly positioned with respect to a golf ball upon addressing, the angle xcex8 of intersection between a horizontal line containing a meeting point on the clubface and a line connecting the meeting point and the center of gravity of the head is in the range of from 0xc2x0 to 29.3xc2x0.
According to another aspect of the present invention, there is provided a head of a No. 7 iron golf club wherein in a state where the head has been correctly positioned with respect to a golf ball upon addressing, the angle xcex8 of intersection between a horizontal line containing a meeting point on the clubface and a line connecting the meeting point and the center of gravity of the head is in the range of from 0xc2x0 to 30.3xc2x0.
According to another aspect of the present invention, there is provided a head of a No. 8 iron golf club wherein in a state where the head has been correctly positioned with respect to a golf ball upon addressing, the angle xcex8 of intersection between a horizontal line containing a meeting point on the clubface and a line connecting the meeting point and the center of gravity of the head is in the range of from 0xc2x0 to 31.0xc2x0.
According to another aspect of the present invention, there is provided a head of a No. 9 iron golf club wherein in a state where the head has been correctly positioned with respect to a golf ball upon addressing, the angle xcex8 of intersection between a horizontal line containing a meeting point on the clubface and a line connecting the meeting point and the center of gravity of the head is in the range of from 0xc2x0 to 31.6xc2x0.
According to another aspect of the present invention, there is provided a head of a pitching wedge iron golf club wherein in a state where the head has been correctly positioned with respect to a golf ball upon addressing, the angle xcex8 of intersection between a horizontal line containing a meeting point on the clubface and a line connecting the meeting point and the center of gravity of the head is in the range of from 0xc2x0 to 30.8xc2x0.
The heads of the No. 2 to 9 and pitching wedge iron golf clubs may be arranged such that in a state where each head has been correctly positioned with respect to a golf ball upon addressing, the centers of gravity of the iron golf clubs lie at approximately equal heights from the ground.
In addition, the present invention provides an iron golf club evaluating method wherein the performance of an iron golf club is evaluated by judging whether or not, in a state where the head of the iron golf club has been correctly positioned with respect to a golf ball upon addressing, the angle xcex8 of intersection between a horizontal line containing a meeting point on the clubface and a line connecting the meeting point and the center of gravity of the head falls within a predetermined angle range.
According to another aspect of the present invention, there is provided a head of an iron golf club wherein a meeting point on the clubface is below a sweet spot on the clubface.
In this case, the release point may be coincident with the sweet spot.
In addition, the present invention provides an iron golf club having any of the foregoing heads.